US4411827A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coprecipitation process for thermionic cathode type materials
Assignee: Individual
•
Filing: 1982-06-23
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Granted: 1983-10-25
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Expires: 2002-06-23
Abstract
Abstract A method for fabricating a homogenous and uniformly sized mixture of alkaline earth metal carbonates found to be especially useful as an emission type coating material for application to a cathodic element of a thermionic vacuum tube.
Inventors
- 👤 David M. Corneille
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:33
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/04; H01J9/042; H01J9/047
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
119 words
A method for producing a homogeneous mixture of uniformly sized, ultrafine, alkaline earth metal carbonates for use as a thermionic emission type coating material which comprises the steps of (1) forming a mixture of alkaline earth metal carbonates composed of about 2 to 10 weight percent calcium carbonate, 10 to 60 weight percent strontium carbonate and the balance barium carbonate; (2) dissolving said mixture in trifluoroethanol to form a solvent mixture; (3) heating said solvent mixture to a temperature of about 60° C. for a period of about five minutes to extract said solvent from said solvent mixture; and (4) recovering the resulting precipitate as a homogeneous, ultrafine mixture of alkaline earth metal carbonates of uniform size and distribution.
Claim 2
Independent Claim
119 words
A method for producing a homogeneous mixture of uniformly sized, ultrafine, alkaline earth metal carbonates for use as a thermionic emission type coating material which comprises the steps of (1) forming a mixture of alkaline earth metal carbonates composed of about 2 to 10 weight percent calcium carbonate, 10 to 60 weight percent strontium carbonate and the balance barium carbonate; (2) dissolving said mixture in trifluoroethanol to form a solvent mixture; (3) heating said solvent mixture to a temperature of about 60° C. for a period of about five minutes to extract said solvent from said solvent mixture; and (4) recovering the resulting precipitate as a homogeneous, ultrafine mixture of alkaline earth metal carbonates of uniform size and distribution.
References Cited (Backward Citations)
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US2985548A
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US3719856A
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US4573683A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-24 | 1987-04-25 | 1987-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-24 | 1991-04-25 | 1991-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-24 | 1995-04-25 | 1995-10-25 | $7700.00 | Window Closed / Lapsed |